An execution-style murder, also known as Chicago-style murder and execution-style killing, is an act of criminal murder where the perpetrator kills at close range a conscious victim who is under the complete physical control of the assailant and who has been left with no course of resistance or escape. Execution style killing is most often a shot to the head, and victims sometimes are killed kneeling. One of the more notorious occurrences of an execution-style murder was the 1929 St. Valentine's Day massacre in Chicago where a number of assailants posed as police officers. Color of authority, however, is not a defining component of the event, as the crimes of Stanley Williams and Dennis Rader also fall into this category. The terminology may derive from the process of binding the victim and killing him/her at close range while conscious. Some thrill killings have variously been described as execution-style murders.

The weapon involved is usually a handgun, though long guns, blunt instruments, and bladed weapons have also been used in killings labeled as execution style, such as the 1993 murder of Bobby Kent in Hollywood, Florida, where Derek Kaufman delivered the fatal blow with an iron club. The method is generally understood to presume such a degree of wanton, premeditated evil that any other crimes undertaken during the incident (e.g., robbery, kidnapping, rape) cannot be considered as motives.